Inadequate physical activity (PA) is considered a major risk factor for cardiometabolic disease. Clinical recommendations endorse achieving healthy PA levels in the primary prevention of cardiovascular disease and type 2 diabetes. The need for wider reaching primary prevention efforts with increasing PA levels as a ?central element? has been suggested by previous studies. PA improvement programs integrated with clinical practice have the potential to reach a large number of at-risk individuals. Although a framework for clinician identification and treatment of people with low PA levels has been developed by the American College of Sports Medicine (ACSM), and clinical PA referral is now endorsed by the American Heart Association (AHA), the practice of identifying and addressing inadequate PA is not common in clinical practice. This proposal aims to improve important aspects of clinical PA referral for primary care patients with low PA and additional cardiometabolic risk factors. Aim 1 of the proposal will determine the efficacy of an inexpensive, convenient, evidence-based online intervention for improving PA levels that is appropriate for adult patients not meeting the US aerobic PA goal of 150 minutes/ week of moderate-vigorous intensity (e.g., brisk walking) PA who also have at least one other common cardiometabolic risk factor (high blood pressure, elevated glucose levels, and/or overweight/obesity). Adult primary care patients (n=54; aged 40-70) meeting the criteria for low PA and additional cardiometabolic risk who can safely increase activity without supervision will be recruited. Participants will be randomized to an active control (to receive a commercial wrist-worn physical activity tracker; PAT) or an online social-cognitive theory-based intervention (3 months of weekly sessions and 9 months maintenance) plus PAT. Primary outcomes will include the change in average step counts/day and percentage meeting the 150 minutes/week activity goal; they will be assessed at 6 and 12 months of follow-up. Secondary outcomes will include body weight, waist circumference, blood pressure, fasting glucose, insulin, cholesterol, triglycerides, and patient-reported outcomes including self-efficacy, quality of life, cost, and experience/satisfaction. Statistics on participant usage of the online platform and tracking tools, participant attitudes/beliefs, and opinions regarding maintenance strategies, will also be collected. We will leverage real world evidence by examining associations between changes in PA levels and important cardiometabolic outcomes that are measured clinically and by identifying EHR measures of patient characteristics that predict changes in PA levels. Methods for dealing with missing data will be considered. The goal of Aim 2 is to develop procedural recommendations for adding PAT data to an Epic-based electronic health record (EHR). Communicating patient PA levels with clinical teams through the EHR, using existing PATs holds value, but there is no consensus on how to accomplish this. We will engage key stakeholders in developing an interdisciplinary set of procedures that considers the needs of health professionals, health systems, researchers, and patients. Completion of these aims will provide pilot data to inform future efforts to develop feasible, effective PA referral programs that can be coordinated with clinical care and will build important collaborative relationships and skills relevant to pragmatic trials.